Question

Find the amount of oxygen present in CO2, if the amount of carbon is

12 gram and also find the amount of carbon dioxide. C:O=3:8 by

mass

2/ CaO + CO2 -------- CaCO3

(5.6gr) (10gr)

Find the mass of CO2?​

Answer 1

Answer:

c + o + o thats equal to 27

Answer 2

Answer:

Molar masses are a helpful way to calculate reaction yields. You have one mole of a substance when the molecular or atomic mass of the substance is equal to the amount you have in grams.

So one mole of H2 - dihydrogen - (with a molecular mass of 2) is 2g.

One mole of Lithium (with a molecular mass of 7) is 7g and so on.

Okay - the atomic mass of carbon is 12 grams per mole. You have 12 grams of carbon, therefore you have one mole.

The atomic mass of oxygen (one atom of oxygen on its own) is 16 grams per mole. You have 32 grams, therefore you have two moles of oxygen atoms. This is the equivalent to one mole of O2 (diatomic oxygen, two oxygen atoms together, which has a molecular mass of 32).

Reacting one mole of carbon with two moles of atomic oxygen (or one mole of O2/molecular oxygen) yields one mole of carbon dioxide.

C + O2 => CO2

(or, to make that clearer)

1 C + 1 O2 => 1 CO2

Therefore one answer to the question (as YOU have written it) is “one mole of CO2”. This is “How much CO2 is formed” in the units of moles.

The mass of one mole of CO2 (which is likely to be the answer your teacher is after), I’ll leave you to find out. But hopefully you should be able to see how moles are converted into grams using atomic or molecular weights.

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John Chapman, Ex Chemistry teacher and author

Updated June 18, 2018